Hidden Hearing Loss–Subjective and Objective Correlation of Cochlear Physiology

Abstract

Purpose: The study is aimed at identifying the co-relation of subjective and objective tests’ that reveal the site of lesion in Hidden Hearing Loss.Methods: A total of 40 participants, between the age range 18 to 25 years were included in this study. They were categorized into two groups. Group 1 – Subjects with extended high frequency (EHF) loss but normal thresholds at conventional frequencies. Group 2 with normal EHF and conventional audiogram results. EHF testing was performed at 10 kHz, 12.5 kHz, 14 kHz, and 16 kHz. Click evoked Auditory Brainstem Response was done to elicit Cochlear Microphonics (CM) and Peak I.Results: Participants with normal EHF thresholds exhibited presence of Peak I and CM, whereas absence of Peak 1 and CM at 70 dB HL and below was seen in the group 1 participants. Results revealed no significant relationship between both groups.Conclusions: The outcome of this study defines the physiology behind Hidden Hearing Loss as the insult to cochlear structures especially OHC’s. This led to a conclusion that there is a strong alliance between EHF loss, absence of CM and Peak I resulting in Auditory dys-synchrony in the far basal regions of the cochlea. This reveals an astonishing impact that alarms young adult population to prevent further incidence at the earliest.